The present invention relates to wheelchairs, and more particularly to a wheelchair which, in addition to functioning as a standard wheelchair, further assists the user to come to a standing position, and stabilizes the user while standing and walking. In addition to its other benefits, this invention provides a mechanism by which a handicapped person may routinely undertake therapy and rehabilitative gait training without the necessity of other specialized equipment and with a minimal amount of assistance. This invention allows the user to enjoy a large range of seating and standing positions, including, among other movement, the user to place their feet on the floor and extend his or her legs at various angles up to and including the locked standing position. The user is thus able to make postural adjustments which provide relief from the discomfort and pain which otherwise results when one is unable to make unconscious body movements or postural adjustments.
The physical and psychological benefits of wheelchairs which bring the user to a standing position have long been recognized. A person who remains seated all of the time may suffer a broad range of complications and discomforts, including skin breakdown, problems with postural stability, difficulties with breathing and swallowing, incontinence, impaired sensation, and pressure ulcers. A variety of different devices have been proposed for relieving these problems by raising a wheelchair user from a seated position to a standing position, or assisting a wheelchair user to maintain a standing position or ambulate with his or her legs. In this regard, two general types of devices are known. The first types of device are wheelchairs which raises the user to a standing position. The second types of device are walkers which attach to a wheelchair or used in conjunction with a wheelchair. The first type of device raises the wheelchair user to a standing position, but retains the user""s feet secured to the footrests or other parts of the wheelchair. Examples of this type of device are found in the following U.S. Pat. Nos.: 4,054,319; 4,067,249; 4,598,944; 5,096,008; 5,366,036; and 5,772,226. While in the standing position in this type of device, the device is generally not propelled by the user""s feet, but instead by other means such as a second person, by the user""s arms, or by a self-contained motor. While many of these devices combine the features of a general purpose wheelchair with a xe2x80x9cstand-upxe2x80x9d mechanism, the geometry of these devices places the users"" body in a position which is not naturally balanced or appropriate for use as a walker.
The second type of device functions as a walker, allowing a wheelchair user not only to stand, but also to ambulate using his or her own feet to propel the device. Examples of this type of device are found in the following U.S. Pat. Nos.: 2,596,055; 3,023,048; 3,398,974; 3,999,778; and 4,948,156. There are known physical benefits in assisting a person to a standing position where the person""s own skeletal structure provides the support. Such benefits include improved bowel and bladder regularity, strengthening of the cardiovascular system, reduction of edema in lower extremities, assisting the lungs in staying clear, improved digestive metabolic process, lessening of muscle spasms and contractions, stretching of tendons and ligaments in lower extremities, and reducing calcium loss in bones.
The inventions proposed for a walker type of device generally disclose an attachment to be used in conjunction with a standard wheelchair. For example, U.S. Pat. No. 3,3998,974 describes a walker attachment which enables the patient to stand up and walk in front of the wheel chair. However, few of the walker devices include a self-contained mechanism for assisting the user in coming to a standing position. One of the few devices which does include such a mechanism is found in U.S. Pat. No. 4,948,156, in which the disclosed transportable frame which can be attached to a wheelchair includes a hand-operated winch mechanism. The user operates the winch to activate a seat harness which pulls the user into a standing position. Another disadvantage of this type of device is that the known walker attachments are generally bulky, not easily stored, increase the total weight of the wheel chair, and constitute yet even further equipment with which a handicapped person is surrounded by and isolated within.
A need exists for a wheelchair which functions both as a wheelchair and as a stander and walker, which is space-efficient, and which brings the user to a standing position with little effort. A need further exists for a wheelchair which enables its user to make postural adjustments, i.e., dynamic seating, to allow the user relief from the discomfort and chronic pain associated with sitting in a single static position.
The present invention is directed to a dynamic seating and walking wheelchair which meets the needs identified above. The disclosed apparatus functions as a conventional wheelchair, but also enables the user to easily achieve a wide range of position from sitting to standing, thereby allowing the user to enjoy postural adjustments as desired. The device also functions as a stander, walker and hands-free walker. Because the invention is generally the same size as a conventional wheelchair, and does not utilize bulky attachments to function as a walker, this device is space efficient. In addition, the present invention is less confining and isolating than the known walkers, the present invention having minimal structural members in front of the user. When functioning as a walker, the present invention provides a stable support platform for the user, allowing the user to propel the walker through the use of the user""s legs and feet, without structural members of the device limiting the user""s range of leg motion. The present invention, when used with appropriate support means such as a harness, will also allow the user to stand and be supported without the use of his or her arms or hands and without any assistance from other persons.
In addition to its other benefits, the present invention may be used for therapeutic purposes, including gait training. The benefits of ambulation are well known, and include increased balance and endurance, and improved range of motion and circulation. The user may use the walking function of the present invention at the user""s personal convenience, greatly increasing the convenience and frequency of therapy. Therapy which otherwise requires the use of special equipment, such as hand rails, and the assistance of others to assist the handicapped person in using therapy equipment, may be conducted at the user""s convenience, resulting in lower expenses for therapy.
One embodiment of the disclosed apparatus comprises a generally horizontal base frame, a plurality of ground-engaging wheels connected to the base frame and a plurality of vertical tracks connected to the base frame in which the vertical tracks extend generally upward from the base frame. A seat carriage, having a vertical frame, an upright seat back and a seat, is slideably attached to the vertical tracks such that the seat carriage may be slid from and positioned at and between a lower position to an upper position and from the upper position to the lower position. The seat carriage may also be stopped at any position between the upper position and the lower position, as desired by the user. The upright seat back is attached to the vertical frame. The seat is pivotally mounted to the vertical frame such that the seat is swingable from a generally horizontal first position extending perpendicularly from the vertical frame to a generally vertical second position parallel to the vertical frame, and back again. The embodiment includes means for raising the seat carriage to the upper position and for lowering the seat carriage to the lower position.
The disclosed apparatus may also be fabricated such that as the seat carriage is raised, the seat simultaneously swings from the generally horizontal first position to the generally vertical second position, and, as the seat carriage is lowered, the seat frame simultaneously swings from the second position to the first position. The seat carriage may be slideably connected to the vertical support members with vertical bearings. The vertical bearings may be connected to the seat carriage with flexible connectors. Various means may be used for raising and lowering the seat carriage. One such means comprises a cable having a first and second end, the first end attached to the seat carriage and the second end attached to a winch adapted to wind and unwind the cable. A second means comprises a cable having a first and second end, the first end attached to the seat carriage and the second end attached to a sheave, the sheave attached to a gearbox and the gearbox coupled to a motor. Another means for raising and lowering the seat carriage comprises a motor coupled to a linear actuator, wherein the linear actuator is connected to the vertical frame. If one of the motor means is used, a motor control switch may be added to allow the user to control the raising and lowering function from the device.
While adaptable to different wheel combinations, the present invention may also comprise a ground-engaging main wheels, and a plurality of ground-engaging support wheels, including front wheels and rear wheels. A seat frame, comprising a left member, a right member and a front member may be substituted for the seat, wherein a left leg support is attached to the left member and the front member of the seat frame and a right leg support is attached to the right member and the front member of the seat frame. When the seat frame is used, a saddle may be added such that when the seat frame is in the first position, the left leg support, the right leg support, and the saddle provide a seating surface for the user, the saddle positioned between the left leg support and the right leg support. The saddle extends forwardly and generally horizontally from the vertical frame. There are different options for attaching the saddle to the vertical frame, including fixed attachment, attaching the saddle with a quick disconnect, or pivotally attaching the saddle so that it swings out of the user""s way.
These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings.